URL shortener app migration

Authors:

As part of our transition away from the hosted apps system and onto the Allura platform, the sfurl URL shortening app is being migrated to the new Allura tool. All of the existing short URLs (e.g., http://p.sf.net/sitedocs/getsupport) will continue to work, but the UI for managing the URLs will now be found at https://sourceforge.net/p/project/url, where project is your project name.

Note, however, that the URL Shortener tool will not be available to install for projects that did not already have the hosted app version.